be deep fear that the assad regime might use chemical warfare against its own people, serin gas, which is so deadly. how concerned? how fearful are the rebels, the civilian population, in northern syria where you are. >> reporter: as fearful as one could possibly manage them to be. this is a population that has no way to protect itself from bullets and bombs. one rebel commander we were talking to has no doubt in his mind that he would, in fact, use this type of weapon ri. he said if you look at the history of this uprising, the asad regime moved onto rockets and then onto air strikes. the next step, as this rebel force is really strengthening its strangle hold on this syrian government is going to be to employ chemical weapons to deliver that final and deadly blow. >> in northern syria for us on the scene, aura, be careful. thanks so much. here in washington, a massive show of force on capital hill. up next, the message some senior citizens are sending lawmakers looming the fiscal cliff. stay with us. you're in "the situation room." ♪ ♪ ♪ [ male announcer ] everyone deserves the